// https://syzkaller.appspot.com/bug?id=fc426eba19283205cbebccf5103e9cc5b3809b2f
// autogenerated by syzkaller (https://github.com/google/syzkaller)

#define _GNU_SOURCE

#include <arpa/inet.h>
#include <endian.h>
#include <errno.h>
#include <fcntl.h>
#include <net/if.h>
#include <net/if_arp.h>
#include <netinet/in.h>
#include <sched.h>
#include <setjmp.h>
#include <stdarg.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <sys/mount.h>
#include <sys/prctl.h>
#include <sys/resource.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/syscall.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>

#include <linux/capability.h>
#include <linux/genetlink.h>
#include <linux/if_addr.h>
#include <linux/if_ether.h>
#include <linux/if_link.h>
#include <linux/if_tun.h>
#include <linux/in6.h>
#include <linux/ip.h>
#include <linux/loop.h>
#include <linux/neighbour.h>
#include <linux/net.h>
#include <linux/netlink.h>
#include <linux/rtnetlink.h>
#include <linux/tcp.h>
#include <linux/veth.h>

#ifndef __NR_memfd_create
#define __NR_memfd_create 319
#endif

static unsigned long long procid;

static bool write_file(const char* file, const char* what, ...)
{
  char buf[1024];
  va_list args;
  va_start(args, what);
  vsnprintf(buf, sizeof(buf), what, args);
  va_end(args);
  buf[sizeof(buf) - 1] = 0;
  int len = strlen(buf);
  int fd = open(file, O_WRONLY | O_CLOEXEC);
  if (fd == -1)
    return false;
  if (write(fd, buf, len) != len) {
    int err = errno;
    close(fd);
    errno = err;
    return false;
  }
  close(fd);
  return true;
}

struct nlmsg {
  char* pos;
  int nesting;
  struct nlattr* nested[8];
  char buf[4096];
};

static void netlink_init(struct nlmsg* nlmsg, int typ, int flags,
                         const void* data, int size)
{
  memset(nlmsg, 0, sizeof(*nlmsg));
  struct nlmsghdr* hdr = (struct nlmsghdr*)nlmsg->buf;
  hdr->nlmsg_type = typ;
  hdr->nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK | flags;
  memcpy(hdr + 1, data, size);
  nlmsg->pos = (char*)(hdr + 1) + NLMSG_ALIGN(size);
}

static void netlink_attr(struct nlmsg* nlmsg, int typ, const void* data,
                         int size)
{
  struct nlattr* attr = (struct nlattr*)nlmsg->pos;
  attr->nla_len = sizeof(*attr) + size;
  attr->nla_type = typ;
  if (size > 0)
    memcpy(attr + 1, data, size);
  nlmsg->pos += NLMSG_ALIGN(attr->nla_len);
}

static int netlink_send_ext(struct nlmsg* nlmsg, int sock, uint16_t reply_type,
                            int* reply_len, bool dofail)
{
  if (nlmsg->pos > nlmsg->buf + sizeof(nlmsg->buf) || nlmsg->nesting)
    exit(1);
  struct nlmsghdr* hdr = (struct nlmsghdr*)nlmsg->buf;
  hdr->nlmsg_len = nlmsg->pos - nlmsg->buf;
  struct sockaddr_nl addr;
  memset(&addr, 0, sizeof(addr));
  addr.nl_family = AF_NETLINK;
  ssize_t n = sendto(sock, nlmsg->buf, hdr->nlmsg_len, 0,
                     (struct sockaddr*)&addr, sizeof(addr));
  if (n != (ssize_t)hdr->nlmsg_len) {
    if (dofail)
      exit(1);
    return -1;
  }
  n = recv(sock, nlmsg->buf, sizeof(nlmsg->buf), 0);
  if (reply_len)
    *reply_len = 0;
  if (n < 0) {
    if (dofail)
      exit(1);
    return -1;
  }
  if (n < (ssize_t)sizeof(struct nlmsghdr)) {
    errno = EINVAL;
    if (dofail)
      exit(1);
    return -1;
  }
  if (hdr->nlmsg_type == NLMSG_DONE)
    return 0;
  if (reply_len && hdr->nlmsg_type == reply_type) {
    *reply_len = n;
    return 0;
  }
  if (n < (ssize_t)(sizeof(struct nlmsghdr) + sizeof(struct nlmsgerr))) {
    errno = EINVAL;
    if (dofail)
      exit(1);
    return -1;
  }
  if (hdr->nlmsg_type != NLMSG_ERROR) {
    errno = EINVAL;
    if (dofail)
      exit(1);
    return -1;
  }
  errno = -((struct nlmsgerr*)(hdr + 1))->error;
  return -errno;
}

static int netlink_send(struct nlmsg* nlmsg, int sock)
{
  return netlink_send_ext(nlmsg, sock, 0, NULL, true);
}

static int netlink_query_family_id(struct nlmsg* nlmsg, int sock,
                                   const char* family_name, bool dofail)
{
  struct genlmsghdr genlhdr;
  memset(&genlhdr, 0, sizeof(genlhdr));
  genlhdr.cmd = CTRL_CMD_GETFAMILY;
  netlink_init(nlmsg, GENL_ID_CTRL, 0, &genlhdr, sizeof(genlhdr));
  netlink_attr(nlmsg, CTRL_ATTR_FAMILY_NAME, family_name,
               strnlen(family_name, GENL_NAMSIZ - 1) + 1);
  int n = 0;
  int err = netlink_send_ext(nlmsg, sock, GENL_ID_CTRL, &n, dofail);
  if (err < 0) {
    return -1;
  }
  uint16_t id = 0;
  struct nlattr* attr = (struct nlattr*)(nlmsg->buf + NLMSG_HDRLEN +
                                         NLMSG_ALIGN(sizeof(genlhdr)));
  for (; (char*)attr < nlmsg->buf + n;
       attr = (struct nlattr*)((char*)attr + NLMSG_ALIGN(attr->nla_len))) {
    if (attr->nla_type == CTRL_ATTR_FAMILY_ID) {
      id = *(uint16_t*)(attr + 1);
      break;
    }
  }
  if (!id) {
    errno = EINVAL;
    return -1;
  }
  recv(sock, nlmsg->buf, sizeof(nlmsg->buf), 0);
  return id;
}

static void netlink_device_change(struct nlmsg* nlmsg, int sock,
                                  const char* name, bool up, const char* master,
                                  const void* mac, int macsize,
                                  const char* new_name)
{
  struct ifinfomsg hdr;
  memset(&hdr, 0, sizeof(hdr));
  if (up)
    hdr.ifi_flags = hdr.ifi_change = IFF_UP;
  hdr.ifi_index = if_nametoindex(name);
  netlink_init(nlmsg, RTM_NEWLINK, 0, &hdr, sizeof(hdr));
  if (new_name)
    netlink_attr(nlmsg, IFLA_IFNAME, new_name, strlen(new_name));
  if (master) {
    int ifindex = if_nametoindex(master);
    netlink_attr(nlmsg, IFLA_MASTER, &ifindex, sizeof(ifindex));
  }
  if (macsize)
    netlink_attr(nlmsg, IFLA_ADDRESS, mac, macsize);
  int err = netlink_send(nlmsg, sock);
  if (err < 0) {
  }
}

static int netlink_add_addr(struct nlmsg* nlmsg, int sock, const char* dev,
                            const void* addr, int addrsize)
{
  struct ifaddrmsg hdr;
  memset(&hdr, 0, sizeof(hdr));
  hdr.ifa_family = addrsize == 4 ? AF_INET : AF_INET6;
  hdr.ifa_prefixlen = addrsize == 4 ? 24 : 120;
  hdr.ifa_scope = RT_SCOPE_UNIVERSE;
  hdr.ifa_index = if_nametoindex(dev);
  netlink_init(nlmsg, RTM_NEWADDR, NLM_F_CREATE | NLM_F_REPLACE, &hdr,
               sizeof(hdr));
  netlink_attr(nlmsg, IFA_LOCAL, addr, addrsize);
  netlink_attr(nlmsg, IFA_ADDRESS, addr, addrsize);
  return netlink_send(nlmsg, sock);
}

static void netlink_add_addr4(struct nlmsg* nlmsg, int sock, const char* dev,
                              const char* addr)
{
  struct in_addr in_addr;
  inet_pton(AF_INET, addr, &in_addr);
  int err = netlink_add_addr(nlmsg, sock, dev, &in_addr, sizeof(in_addr));
  if (err < 0) {
  }
}

static void netlink_add_addr6(struct nlmsg* nlmsg, int sock, const char* dev,
                              const char* addr)
{
  struct in6_addr in6_addr;
  inet_pton(AF_INET6, addr, &in6_addr);
  int err = netlink_add_addr(nlmsg, sock, dev, &in6_addr, sizeof(in6_addr));
  if (err < 0) {
  }
}

static void netlink_add_neigh(struct nlmsg* nlmsg, int sock, const char* name,
                              const void* addr, int addrsize, const void* mac,
                              int macsize)
{
  struct ndmsg hdr;
  memset(&hdr, 0, sizeof(hdr));
  hdr.ndm_family = addrsize == 4 ? AF_INET : AF_INET6;
  hdr.ndm_ifindex = if_nametoindex(name);
  hdr.ndm_state = NUD_PERMANENT;
  netlink_init(nlmsg, RTM_NEWNEIGH, NLM_F_EXCL | NLM_F_CREATE, &hdr,
               sizeof(hdr));
  netlink_attr(nlmsg, NDA_DST, addr, addrsize);
  netlink_attr(nlmsg, NDA_LLADDR, mac, macsize);
  int err = netlink_send(nlmsg, sock);
  if (err < 0) {
  }
}

static struct nlmsg nlmsg;

static int tunfd = -1;

#define TUN_IFACE "syz_tun"
#define LOCAL_MAC 0xaaaaaaaaaaaa
#define REMOTE_MAC 0xaaaaaaaaaabb
#define LOCAL_IPV4 "172.20.20.170"
#define REMOTE_IPV4 "172.20.20.187"
#define LOCAL_IPV6 "fe80::aa"
#define REMOTE_IPV6 "fe80::bb"

#define IFF_NAPI 0x0010

static void initialize_tun(void)
{
  tunfd = open("/dev/net/tun", O_RDWR | O_NONBLOCK);
  if (tunfd == -1) {
    printf("tun: can't open /dev/net/tun: please enable CONFIG_TUN=y\n");
    printf("otherwise fuzzing or reproducing might not work as intended\n");
    return;
  }
  const int kTunFd = 200;
  if (dup2(tunfd, kTunFd) < 0)
    exit(1);
  close(tunfd);
  tunfd = kTunFd;
  struct ifreq ifr;
  memset(&ifr, 0, sizeof(ifr));
  strncpy(ifr.ifr_name, TUN_IFACE, IFNAMSIZ);
  ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
  if (ioctl(tunfd, TUNSETIFF, (void*)&ifr) < 0) {
    exit(1);
  }
  char sysctl[64];
  sprintf(sysctl, "/proc/sys/net/ipv6/conf/%s/accept_dad", TUN_IFACE);
  write_file(sysctl, "0");
  sprintf(sysctl, "/proc/sys/net/ipv6/conf/%s/router_solicitations", TUN_IFACE);
  write_file(sysctl, "0");
  int sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
  if (sock == -1)
    exit(1);
  netlink_add_addr4(&nlmsg, sock, TUN_IFACE, LOCAL_IPV4);
  netlink_add_addr6(&nlmsg, sock, TUN_IFACE, LOCAL_IPV6);
  uint64_t macaddr = REMOTE_MAC;
  struct in_addr in_addr;
  inet_pton(AF_INET, REMOTE_IPV4, &in_addr);
  netlink_add_neigh(&nlmsg, sock, TUN_IFACE, &in_addr, sizeof(in_addr),
                    &macaddr, ETH_ALEN);
  struct in6_addr in6_addr;
  inet_pton(AF_INET6, REMOTE_IPV6, &in6_addr);
  netlink_add_neigh(&nlmsg, sock, TUN_IFACE, &in6_addr, sizeof(in6_addr),
                    &macaddr, ETH_ALEN);
  macaddr = LOCAL_MAC;
  netlink_device_change(&nlmsg, sock, TUN_IFACE, true, 0, &macaddr, ETH_ALEN,
                        NULL);
  close(sock);
}

#define MAX_FDS 30

//% This code is derived from puff.{c,h}, found in the zlib development. The
//% original files come with the following copyright notice:

//% Copyright (C) 2002-2013 Mark Adler, all rights reserved
//% version 2.3, 21 Jan 2013
//% This software is provided 'as-is', without any express or implied
//% warranty.  In no event will the author be held liable for any damages
//% arising from the use of this software.
//% Permission is granted to anyone to use this software for any purpose,
//% including commercial applications, and to alter it and redistribute it
//% freely, subject to the following restrictions:
//% 1. The origin of this software must not be misrepresented; you must not
//%    claim that you wrote the original software. If you use this software
//%    in a product, an acknowledgment in the product documentation would be
//%    appreciated but is not required.
//% 2. Altered source versions must be plainly marked as such, and must not be
//%    misrepresented as being the original software.
//% 3. This notice may not be removed or altered from any source distribution.
//% Mark Adler    madler@alumni.caltech.edu

//% BEGIN CODE DERIVED FROM puff.{c,h}

#define MAXBITS 15
#define MAXLCODES 286
#define MAXDCODES 30
#define MAXCODES (MAXLCODES + MAXDCODES)
#define FIXLCODES 288

struct puff_state {
  unsigned char* out;
  unsigned long outlen;
  unsigned long outcnt;
  const unsigned char* in;
  unsigned long inlen;
  unsigned long incnt;
  int bitbuf;
  int bitcnt;
  jmp_buf env;
};
static int puff_bits(struct puff_state* s, int need)
{
  long val = s->bitbuf;
  while (s->bitcnt < need) {
    if (s->incnt == s->inlen)
      longjmp(s->env, 1);
    val |= (long)(s->in[s->incnt++]) << s->bitcnt;
    s->bitcnt += 8;
  }
  s->bitbuf = (int)(val >> need);
  s->bitcnt -= need;
  return (int)(val & ((1L << need) - 1));
}
static int puff_stored(struct puff_state* s)
{
  s->bitbuf = 0;
  s->bitcnt = 0;
  if (s->incnt + 4 > s->inlen)
    return 2;
  unsigned len = s->in[s->incnt++];
  len |= s->in[s->incnt++] << 8;
  if (s->in[s->incnt++] != (~len & 0xff) ||
      s->in[s->incnt++] != ((~len >> 8) & 0xff))
    return -2;
  if (s->incnt + len > s->inlen)
    return 2;
  if (s->outcnt + len > s->outlen)
    return 1;
  for (; len--; s->outcnt++, s->incnt++) {
    if (s->in[s->incnt])
      s->out[s->outcnt] = s->in[s->incnt];
  }
  return 0;
}
struct puff_huffman {
  short* count;
  short* symbol;
};
static int puff_decode(struct puff_state* s, const struct puff_huffman* h)
{
  int first = 0;
  int index = 0;
  int bitbuf = s->bitbuf;
  int left = s->bitcnt;
  int code = first = index = 0;
  int len = 1;
  short* next = h->count + 1;
  while (1) {
    while (left--) {
      code |= bitbuf & 1;
      bitbuf >>= 1;
      int count = *next++;
      if (code - count < first) {
        s->bitbuf = bitbuf;
        s->bitcnt = (s->bitcnt - len) & 7;
        return h->symbol[index + (code - first)];
      }
      index += count;
      first += count;
      first <<= 1;
      code <<= 1;
      len++;
    }
    left = (MAXBITS + 1) - len;
    if (left == 0)
      break;
    if (s->incnt == s->inlen)
      longjmp(s->env, 1);
    bitbuf = s->in[s->incnt++];
    if (left > 8)
      left = 8;
  }
  return -10;
}
static int puff_construct(struct puff_huffman* h, const short* length, int n)
{
  int len;
  for (len = 0; len <= MAXBITS; len++)
    h->count[len] = 0;
  int symbol;
  for (symbol = 0; symbol < n; symbol++)
    (h->count[length[symbol]])++;
  if (h->count[0] == n)
    return 0;
  int left = 1;
  for (len = 1; len <= MAXBITS; len++) {
    left <<= 1;
    left -= h->count[len];
    if (left < 0)
      return left;
  }
  short offs[MAXBITS + 1];
  offs[1] = 0;
  for (len = 1; len < MAXBITS; len++)
    offs[len + 1] = offs[len] + h->count[len];
  for (symbol = 0; symbol < n; symbol++)
    if (length[symbol] != 0)
      h->symbol[offs[length[symbol]]++] = symbol;
  return left;
}
static int puff_codes(struct puff_state* s, const struct puff_huffman* lencode,
                      const struct puff_huffman* distcode)
{
  static const short lens[29] = {3,  4,  5,  6,   7,   8,   9,   10,  11, 13,
                                 15, 17, 19, 23,  27,  31,  35,  43,  51, 59,
                                 67, 83, 99, 115, 131, 163, 195, 227, 258};
  static const short lext[29] = {0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2,
                                 2, 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 0};
  static const short dists[30] = {
      1,    2,    3,    4,    5,    7,    9,    13,    17,    25,
      33,   49,   65,   97,   129,  193,  257,  385,   513,   769,
      1025, 1537, 2049, 3073, 4097, 6145, 8193, 12289, 16385, 24577};
  static const short dext[30] = {0, 0, 0,  0,  1,  1,  2,  2,  3,  3,
                                 4, 4, 5,  5,  6,  6,  7,  7,  8,  8,
                                 9, 9, 10, 10, 11, 11, 12, 12, 13, 13};
  int symbol;
  do {
    symbol = puff_decode(s, lencode);
    if (symbol < 0)
      return symbol;
    if (symbol < 256) {
      if (s->outcnt == s->outlen)
        return 1;
      if (symbol)
        s->out[s->outcnt] = symbol;
      s->outcnt++;
    } else if (symbol > 256) {
      symbol -= 257;
      if (symbol >= 29)
        return -10;
      int len = lens[symbol] + puff_bits(s, lext[symbol]);
      symbol = puff_decode(s, distcode);
      if (symbol < 0)
        return symbol;
      unsigned dist = dists[symbol] + puff_bits(s, dext[symbol]);
      if (dist > s->outcnt)
        return -11;
      if (s->outcnt + len > s->outlen)
        return 1;
      while (len--) {
        if (dist <= s->outcnt && s->out[s->outcnt - dist])
          s->out[s->outcnt] = s->out[s->outcnt - dist];
        s->outcnt++;
      }
    }
  } while (symbol != 256);
  return 0;
}
static int puff_fixed(struct puff_state* s)
{
  static int virgin = 1;
  static short lencnt[MAXBITS + 1], lensym[FIXLCODES];
  static short distcnt[MAXBITS + 1], distsym[MAXDCODES];
  static struct puff_huffman lencode, distcode;
  if (virgin) {
    lencode.count = lencnt;
    lencode.symbol = lensym;
    distcode.count = distcnt;
    distcode.symbol = distsym;
    short lengths[FIXLCODES];
    int symbol;
    for (symbol = 0; symbol < 144; symbol++)
      lengths[symbol] = 8;
    for (; symbol < 256; symbol++)
      lengths[symbol] = 9;
    for (; symbol < 280; symbol++)
      lengths[symbol] = 7;
    for (; symbol < FIXLCODES; symbol++)
      lengths[symbol] = 8;
    puff_construct(&lencode, lengths, FIXLCODES);
    for (symbol = 0; symbol < MAXDCODES; symbol++)
      lengths[symbol] = 5;
    puff_construct(&distcode, lengths, MAXDCODES);
    virgin = 0;
  }
  return puff_codes(s, &lencode, &distcode);
}
static int puff_dynamic(struct puff_state* s)
{
  static const short order[19] = {16, 17, 18, 0, 8,  7, 9,  6, 10, 5,
                                  11, 4,  12, 3, 13, 2, 14, 1, 15};
  int nlen = puff_bits(s, 5) + 257;
  int ndist = puff_bits(s, 5) + 1;
  int ncode = puff_bits(s, 4) + 4;
  if (nlen > MAXLCODES || ndist > MAXDCODES)
    return -3;
  short lengths[MAXCODES];
  int index;
  for (index = 0; index < ncode; index++)
    lengths[order[index]] = puff_bits(s, 3);
  for (; index < 19; index++)
    lengths[order[index]] = 0;
  short lencnt[MAXBITS + 1], lensym[MAXLCODES];
  struct puff_huffman lencode = {lencnt, lensym};
  int err = puff_construct(&lencode, lengths, 19);
  if (err != 0)
    return -4;
  index = 0;
  while (index < nlen + ndist) {
    int symbol;
    int len;
    symbol = puff_decode(s, &lencode);
    if (symbol < 0)
      return symbol;
    if (symbol < 16)
      lengths[index++] = symbol;
    else {
      len = 0;
      if (symbol == 16) {
        if (index == 0)
          return -5;
        len = lengths[index - 1];
        symbol = 3 + puff_bits(s, 2);
      } else if (symbol == 17)
        symbol = 3 + puff_bits(s, 3);
      else
        symbol = 11 + puff_bits(s, 7);
      if (index + symbol > nlen + ndist)
        return -6;
      while (symbol--)
        lengths[index++] = len;
    }
  }
  if (lengths[256] == 0)
    return -9;
  err = puff_construct(&lencode, lengths, nlen);
  if (err && (err < 0 || nlen != lencode.count[0] + lencode.count[1]))
    return -7;
  short distcnt[MAXBITS + 1], distsym[MAXDCODES];
  struct puff_huffman distcode = {distcnt, distsym};
  err = puff_construct(&distcode, lengths + nlen, ndist);
  if (err && (err < 0 || ndist != distcode.count[0] + distcode.count[1]))
    return -8;
  return puff_codes(s, &lencode, &distcode);
}
static int puff(unsigned char* dest, unsigned long* destlen,
                const unsigned char* source, unsigned long sourcelen)
{
  struct puff_state s = {
      .out = dest,
      .outlen = *destlen,
      .outcnt = 0,
      .in = source,
      .inlen = sourcelen,
      .incnt = 0,
      .bitbuf = 0,
      .bitcnt = 0,
  };
  int err;
  if (setjmp(s.env) != 0)
    err = 2;
  else {
    int last;
    do {
      last = puff_bits(&s, 1);
      int type = puff_bits(&s, 2);
      err = type == 0 ? puff_stored(&s)
                      : (type == 1 ? puff_fixed(&s)
                                   : (type == 2 ? puff_dynamic(&s) : -1));
      if (err != 0)
        break;
    } while (!last);
  }
  *destlen = s.outcnt;
  return err;
}

//% END CODE DERIVED FROM puff.{c,h}

#define ZLIB_HEADER_WIDTH 2

static int puff_zlib_to_file(const unsigned char* source,
                             unsigned long sourcelen, int dest_fd)
{
  if (sourcelen < ZLIB_HEADER_WIDTH)
    return 0;
  source += ZLIB_HEADER_WIDTH;
  sourcelen -= ZLIB_HEADER_WIDTH;
  const unsigned long max_destlen = 132 << 20;
  void* ret = mmap(0, max_destlen, PROT_WRITE | PROT_READ,
                   MAP_PRIVATE | MAP_ANON, -1, 0);
  if (ret == MAP_FAILED)
    return -1;
  unsigned char* dest = (unsigned char*)ret;
  unsigned long destlen = max_destlen;
  int err = puff(dest, &destlen, source, sourcelen);
  if (err) {
    munmap(dest, max_destlen);
    errno = -err;
    return -1;
  }
  if (write(dest_fd, dest, destlen) != (ssize_t)destlen) {
    munmap(dest, max_destlen);
    return -1;
  }
  return munmap(dest, destlen);
}

static int setup_loop_device(unsigned char* data, unsigned long size,
                             const char* loopname, int* loopfd_p)
{
  int err = 0, loopfd = -1;
  int memfd = syscall(__NR_memfd_create, "syzkaller", 0);
  if (memfd == -1) {
    err = errno;
    goto error;
  }
  if (puff_zlib_to_file(data, size, memfd)) {
    err = errno;
    goto error_close_memfd;
  }
  loopfd = open(loopname, O_RDWR);
  if (loopfd == -1) {
    err = errno;
    goto error_close_memfd;
  }
  if (ioctl(loopfd, LOOP_SET_FD, memfd)) {
    if (errno != EBUSY) {
      err = errno;
      goto error_close_loop;
    }
    ioctl(loopfd, LOOP_CLR_FD, 0);
    usleep(1000);
    if (ioctl(loopfd, LOOP_SET_FD, memfd)) {
      err = errno;
      goto error_close_loop;
    }
  }
  close(memfd);
  *loopfd_p = loopfd;
  return 0;

error_close_loop:
  close(loopfd);
error_close_memfd:
  close(memfd);
error:
  errno = err;
  return -1;
}

static long syz_mount_image(volatile long fsarg, volatile long dir,
                            volatile long flags, volatile long optsarg,
                            volatile long change_dir,
                            volatile unsigned long size, volatile long image)
{
  unsigned char* data = (unsigned char*)image;
  int res = -1, err = 0, loopfd = -1, need_loop_device = !!size;
  char* mount_opts = (char*)optsarg;
  char* target = (char*)dir;
  char* fs = (char*)fsarg;
  char* source = NULL;
  char loopname[64];
  if (need_loop_device) {
    memset(loopname, 0, sizeof(loopname));
    snprintf(loopname, sizeof(loopname), "/dev/loop%llu", procid);
    if (setup_loop_device(data, size, loopname, &loopfd) == -1)
      return -1;
    source = loopname;
  }
  mkdir(target, 0777);
  char opts[256];
  memset(opts, 0, sizeof(opts));
  if (strlen(mount_opts) > (sizeof(opts) - 32)) {
  }
  strncpy(opts, mount_opts, sizeof(opts) - 32);
  if (strcmp(fs, "iso9660") == 0) {
    flags |= MS_RDONLY;
  } else if (strncmp(fs, "ext", 3) == 0) {
    bool has_remount_ro = false;
    char* remount_ro_start = strstr(opts, "errors=remount-ro");
    if (remount_ro_start != NULL) {
      char after = *(remount_ro_start + strlen("errors=remount-ro"));
      char before = remount_ro_start == opts ? '\0' : *(remount_ro_start - 1);
      has_remount_ro = ((before == '\0' || before == ',') &&
                        (after == '\0' || after == ','));
    }
    if (strstr(opts, "errors=panic") || !has_remount_ro)
      strcat(opts, ",errors=continue");
  } else if (strcmp(fs, "xfs") == 0) {
    strcat(opts, ",nouuid");
  }
  res = mount(source, target, fs, flags, opts);
  if (res == -1) {
    err = errno;
    goto error_clear_loop;
  }
  res = open(target, O_RDONLY | O_DIRECTORY);
  if (res == -1) {
    err = errno;
    goto error_clear_loop;
  }
  if (change_dir) {
    res = chdir(target);
    if (res == -1) {
      err = errno;
    }
  }

error_clear_loop:
  if (need_loop_device) {
    ioctl(loopfd, LOOP_CLR_FD, 0);
    close(loopfd);
  }
  errno = err;
  return res;
}

static void setup_common()
{
  if (mount(0, "/sys/fs/fuse/connections", "fusectl", 0, 0)) {
  }
}

static void setup_binderfs()
{
  if (mkdir("/dev/binderfs", 0777)) {
  }
  if (mount("binder", "/dev/binderfs", "binder", 0, NULL)) {
  }
  if (symlink("/dev/binderfs", "./binderfs")) {
  }
}

static void loop();

static void sandbox_common()
{
  prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0);
  setsid();
  struct rlimit rlim;
  rlim.rlim_cur = rlim.rlim_max = (200 << 20);
  setrlimit(RLIMIT_AS, &rlim);
  rlim.rlim_cur = rlim.rlim_max = 32 << 20;
  setrlimit(RLIMIT_MEMLOCK, &rlim);
  rlim.rlim_cur = rlim.rlim_max = 136 << 20;
  setrlimit(RLIMIT_FSIZE, &rlim);
  rlim.rlim_cur = rlim.rlim_max = 1 << 20;
  setrlimit(RLIMIT_STACK, &rlim);
  rlim.rlim_cur = rlim.rlim_max = 128 << 20;
  setrlimit(RLIMIT_CORE, &rlim);
  rlim.rlim_cur = rlim.rlim_max = 256;
  setrlimit(RLIMIT_NOFILE, &rlim);
  if (unshare(CLONE_NEWNS)) {
  }
  if (mount(NULL, "/", NULL, MS_REC | MS_PRIVATE, NULL)) {
  }
  if (unshare(CLONE_NEWIPC)) {
  }
  if (unshare(0x02000000)) {
  }
  if (unshare(CLONE_NEWUTS)) {
  }
  if (unshare(CLONE_SYSVSEM)) {
  }
  typedef struct {
    const char* name;
    const char* value;
  } sysctl_t;
  static const sysctl_t sysctls[] = {
      {"/proc/sys/kernel/shmmax", "16777216"},
      {"/proc/sys/kernel/shmall", "536870912"},
      {"/proc/sys/kernel/shmmni", "1024"},
      {"/proc/sys/kernel/msgmax", "8192"},
      {"/proc/sys/kernel/msgmni", "1024"},
      {"/proc/sys/kernel/msgmnb", "1024"},
      {"/proc/sys/kernel/sem", "1024 1048576 500 1024"},
  };
  unsigned i;
  for (i = 0; i < sizeof(sysctls) / sizeof(sysctls[0]); i++)
    write_file(sysctls[i].name, sysctls[i].value);
}

static int wait_for_loop(int pid)
{
  if (pid < 0)
    exit(1);
  int status = 0;
  while (waitpid(-1, &status, __WALL) != pid) {
  }
  return WEXITSTATUS(status);
}

static void drop_caps(void)
{
  struct __user_cap_header_struct cap_hdr = {};
  struct __user_cap_data_struct cap_data[2] = {};
  cap_hdr.version = _LINUX_CAPABILITY_VERSION_3;
  cap_hdr.pid = getpid();
  if (syscall(SYS_capget, &cap_hdr, &cap_data))
    exit(1);
  const int drop = (1 << CAP_SYS_PTRACE) | (1 << CAP_SYS_NICE);
  cap_data[0].effective &= ~drop;
  cap_data[0].permitted &= ~drop;
  cap_data[0].inheritable &= ~drop;
  if (syscall(SYS_capset, &cap_hdr, &cap_data))
    exit(1);
}

static int do_sandbox_none(void)
{
  if (unshare(CLONE_NEWPID)) {
  }
  int pid = fork();
  if (pid != 0)
    return wait_for_loop(pid);
  setup_common();
  sandbox_common();
  drop_caps();
  if (unshare(CLONE_NEWNET)) {
  }
  write_file("/proc/sys/net/ipv4/ping_group_range", "0 65535");
  initialize_tun();
  setup_binderfs();
  loop();
  exit(1);
}

static int inject_fault(int nth)
{
  int fd;
  fd = open("/proc/thread-self/fail-nth", O_RDWR);
  if (fd == -1)
    exit(1);
  char buf[16];
  sprintf(buf, "%d", nth);
  if (write(fd, buf, strlen(buf)) != (ssize_t)strlen(buf))
    exit(1);
  return fd;
}

static void close_fds()
{
  for (int fd = 3; fd < MAX_FDS; fd++)
    close(fd);
}

static void setup_fault()
{
  static struct {
    const char* file;
    const char* val;
    bool fatal;
  } files[] = {
      {"/sys/kernel/debug/failslab/ignore-gfp-wait", "N", true},
      {"/sys/kernel/debug/fail_futex/ignore-private", "N", false},
      {"/sys/kernel/debug/fail_page_alloc/ignore-gfp-highmem", "N", false},
      {"/sys/kernel/debug/fail_page_alloc/ignore-gfp-wait", "N", false},
      {"/sys/kernel/debug/fail_page_alloc/min-order", "0", false},
  };
  unsigned i;
  for (i = 0; i < sizeof(files) / sizeof(files[0]); i++) {
    if (!write_file(files[i].file, files[i].val)) {
      if (files[i].fatal)
        exit(1);
    }
  }
}

void loop(void)
{
  memcpy((void*)0x20000000, "udf\000", 4);
  memcpy((void*)0x20000080,
         "\023\023w\305\3745\324\024T\325\324\035)\255\032`)"
         "Y\201F\346\276\026nA\255\r\275@T\003<\2373\273\332\202$"
         "\242\363\327r\347cnH\263<\277p\203r\350\361\271\223>"
         "\305\022wC\276\"\006 \236\360-\371\313\362\366\350\200\3238/\000",
         78);
  memcpy((void*)0x20000200, "uid=ignore", 10);
  *(uint8_t*)0x2000020a = 0x2c;
  memcpy((void*)0x2000020b, "uid", 3);
  *(uint8_t*)0x2000020e = 0x3d;
  sprintf((char*)0x2000020f, "%020llu", (long long)0);
  *(uint8_t*)0x20000223 = 0x2c;
  memcpy((void*)0x20000224, "partition", 9);
  *(uint8_t*)0x2000022d = 0x3d;
  sprintf((char*)0x2000022e, "%020llu", (long long)3);
  *(uint8_t*)0x20000242 = 0x2c;
  *(uint8_t*)0x20000243 = 0;
  memcpy(
      (void*)0x20000a40,
      "\x78\x9c\xec\xdb\x4b\x6c\x1b\x55\x17\xc0\xf1\x73\x3c\xb6\xeb\xb8\xf9\x3e"
      "\x9c\x34\xa4\x2d\xaa\x8a\x25\x90\x08\x2d\x4d\x93\x38\xa4\xad\x82\x84\xf2"
      "\x20\x02\xa9\x6d\x20\x69\x40\x54\x3c\x14\x62\x27\x98\x38\x71\x14\xa7\x90"
      "\x54\x2d\xcd\x12\xd8\xb1\xe8\x92\x25\x5b\x16\xac\x10\x5b\x54\x89\x25\x62"
      "\x81\x82\x50\x77\xa5\x1b\x36\x5e\x51\x76\x45\x77\x3c\x2f\xbb\x79\x38\x24"
      "\xf1\x34\xcd\xff\x57\xb5\x77\x66\x7c\xec\xde\x7b\x8f\xc7\xf7\x5c\x2b\x11"
      "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
      "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
      "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x20\x32\xf8\xda\x40\x57\xb7"
      "\x86\xdd\x0b\x00\x00\xd0\x48\x97\xc7\xc7\xba\x32\xac\xff\x00\x00\x1c\x28"
      "\x57\xd8\xff\x03\x00\x00\x1c\x24\x2a\x96\xfc\x21\x2a\x67\x66\xcb\x7a\xc9"
      "\x3e\xaf\x48\x5c\xcc\xcf\x5f\x5b\x9e\x18\x1e\x59\xff\x69\x4d\x2a\x2a\x11"
      "\xb1\xec\x78\xf3\x37\xd1\xdd\x93\xe9\x7d\xb9\xef\xdc\x79\xb7\xdd\xfc\xf9"
      "\xbb\xed\xb8\x8c\x8e\x5f\x19\x48\x0f\x15\xe7\x16\x16\x73\xa5\x52\x2e\x9b"
      "\x9e\x98\xcf\x4f\x15\xb3\xb9\xba\x5f\x61\xa7\xcf\xaf\x75\xca\x9e\x80\xf4"
      "\xdc\xec\xb5\xec\xf4\x74\x29\xdd\xd3\x99\xa9\x7a\x78\x39\x75\xff\xd0\xe1"
      "\xf6\x54\x7f\xdf\xfb\x43\x71\x37\x76\x62\x78\x64\x64\x3c\x10\x13\x8d\xfd"
      "\xe7\xff\xfd\x11\x1b\x55\xf8\x71\xb1\xe4\x45\x51\xf9\xe4\x87\xef\xf4\xb2"
      "\x88\x44\x64\xe7\x73\xb1\xc5\x7b\x67\xaf\x35\xd9\x83\x38\x65\x0f\x62\x62"
      "\x78\xc4\x1e\x48\x21\x3f\x39\xbf\x64\x1e\xd4\x88\x13\x15\xa9\x9e\x93\xb8"
      "\x3b\x47\x0d\xc8\xc5\x8e\x44\x44\x4c\xbf\x34\xbe\x3b\x7b\xb6\x98\x58\xf2"
      "\xa3\xa8\x0c\x9e\x2d\xeb\xa8\x88\x58\xee\x3c\x9c\xb6\xbf\x18\xae\xab\x3f"
      "\x61\x88\x9a\xad\xab\x88\x74\xc8\x3e\xc8\xd9\x63\xec\x90\x58\xf2\xa1\xa8"
      "\xdc\x39\x9b\x92\x37\x9d\x79\xb5\xf3\x1f\x17\xb9\x11\x76\xe7\xb0\xe7\xa2"
      "\xce\xfd\x5f\xd4\xb2\xbe\x65\x7f\x1e\x98\xfb\xc9\x7c\x6c\x5e\x7c\x3b\xfd"
      "\xc6\xfc\x74\x31\x10\xab\x11\xe7\x8e\xda\xef\xeb\x43\x23\x3d\xe6\x9f\x4d"
      "\x09\xb1\x64\xd4\xbe\xe3\xcb\x3a\x16\x76\x67\xd0\x70\x4d\x62\xc9\x9c\xa8"
      "\xc4\xbf\xfe\xd4\xae\x2b\xc4\xae\x4b\x9f\xea\x3f\x77\xf2\xd9\x0b\xc1\x0a"
      "\xe3\xe8\x16\xaf\x63\x62\x3b\x9d\x9b\xab\x9e\x35\x39\xe6\x94\x0e\x1a\x31"
      "\x7f\x76\x7f\x5c\xa8\x4f\x42\x2d\xf9\x53\x54\x1e\xfc\x9e\xb0\xcf\x3b\xdc"
      "\x35\x40\x64\xf5\x61\xb8\x5d\x43\x23\xa8\x25\x05\x51\xf9\xe7\x66\x59\xb5"
      "\x66\x5f\x6a\x05\xf6\xf7\x9e\xfd\xbe\xf6\xef\x6d\xff\x9b\x12\x43\xc5\x85"
      "\x95\xc5\xfc\xcc\xc7\x4b\xeb\x3e\x9e\x4c\x0c\x7c\x54\x5a\x5a\x9c\x9c\x5a"
      "\xff\xe1\xca\xde\xd5\x0a\x5e\xd9\x6a\x1f\x5b\x2b\xb2\xbd\x2d\x59\x52\x2b"
      "\x3b\xbe\x2f\x3e\x2b\x7b\xcf\x73\xf6\x00\xff\xab\x9c\xf9\xbd\xf9\xf6\x86"
      "\xff\x5e\xe8\xa8\x69\x5d\xc1\xf7\x4f\x3d\xc7\x75\xef\x62\xb7\x51\x47\x99"
      "\x3e\xa9\x5a\x72\x4f\x54\xa6\x3f\x38\x56\x59\x67\x24\xb9\xed\xb9\x39\x08"
      "\x4c\xfe\x47\x44\xa5\x54\xfe\x45\xdd\x4c\x3b\xf9\x8f\x56\xce\x02\xf9\x7f"
      "\xc5\x9f\xbf\x84\x56\xb7\x1e\x3b\xb7\xff\xaf\x7c\xaf\xe5\xd6\x12\xc7\xaf"
      "\xb6\x6d\x74\x7d\x2f\xf2\x6f\xfa\x64\xf2\xff\xae\xa8\x0c\xfe\x7d\xcc\xf9"
      "\x4e\xa3\x92\x7f\xab\x26\xd6\xc4\xb5\x8b\xca\x7b\xb7\x4f\x38\x71\x91\xb8"
      "\x89\x8b\xba\xc3\xa9\xbc\xe2\x74\xbe\x90\xeb\x32\xb1\x0f\x45\xa5\xf5\x67"
      "\x37\x56\xec\xd8\xa4\x13\x7b\xc4\x8f\xed\x36\xb1\x25\x51\xf9\xf2\x4e\x75"
      "\xec\x61\x27\xb6\xcd\x8f\xed\x31\xb1\x6b\xa2\x72\xf7\xb7\xf5\x63\x9f\xf6"
      "\x63\x33\x26\x76\xc5\xe4\xeb\x6e\xda\x8d\x4d\x9a\xd8\x93\x4e\x6c\xbb\x1f"
      "\xdb\x39\x55\x2c\x64\xb7\x9a\x56\x93\xff\x1e\x51\x79\xe7\xd6\xeb\xea\x8e"
      "\x79\xc3\xfc\x07\xee\xff\xd5\x9a\xd6\xf3\x48\xce\x37\x3f\xde\xad\xfc\xa7"
      "\x02\xd7\x56\x9d\xbc\x5e\x75\xf2\x1f\xdd\x22\xff\x5f\x89\xca\xca\x5f\x27"
      "\xdc\x71\xdb\x73\xef\xbe\xad\x5a\xec\x7f\xfd\xfc\x9b\x5a\xf9\xfb\xdb\xd5"
      "\xb1\xee\x86\xb2\xd5\x8f\xed\xae\x77\x58\x61\x33\xf9\x6f\x11\x95\xfb\xaf"
      "\xae\x79\x63\x76\xc6\xe6\x9c\xfa\x19\x0a\xe6\xff\x99\x68\x75\xeb\xcd\x6b"
      "\x48\xf9\x6f\x09\x5c\x4b\x39\xfd\x8a\x6f\x73\x2e\x0e\xa2\xd2\xca\xf5\xd9"
      "\xc9\x42\x21\xb7\xc8\x01\x07\x1c\x70\xe0\x1d\x84\xfd\xc9\x84\x46\x30\xeb"
      "\xff\x98\x59\xd5\xfb\x2c\x75\xeb\x18\x67\xfd\x6f\xae\x9c\xf9\x15\xd3\x83"
      "\xcf\xfd\xf5\xbf\xbf\xa6\xf5\x84\xb4\xfe\xb7\x06\xae\xf5\x3b\x55\x4b\x2c"
      "\x2a\x92\x58\x9a\x5b\x88\x1d\x15\x49\x94\x56\xae\x9f\xc9\xcf\x4d\xce\xe4"
      "\x66\x72\xf3\x99\xde\xbe\xae\x9e\x0b\xbd\x5d\x99\xf3\xb1\xb8\x5b\xdc\xf9"
      "\x47\x75\xcf\xdd\x93\xc0\xe4\xff\xb4\xa8\xdc\xfc\xe9\x57\x6f\x1f\x53\x5d"
      "\xff\xad\x5f\xff\x27\x6b\x5a\x4f\x48\xf9\x3f\x12\x1c\x53\x55\x5d\x53\xf7"
      "\x54\x1c\x48\x26\xff\xcd\xa2\xd2\x77\x6f\xcd\xdb\x6f\x6e\x56\xff\xbb\xfb"
      "\xff\x8e\xe7\xaa\x5b\xef\xfe\x0b\x29\xff\x6d\x81\x6b\x29\xa7\x5f\xcd\xdb"
      "\x9c\x0b\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\xd8\x4f\x92"
      "\x6a\xc9\xf3\xa2\xb2\x3c\xf6\x92\xba\xbf\x43\x54\xcf\xcf\xff\x65\x6b\x5a"
      "\x4f\x48\x3f\xff\xd5\x1e\xb8\x96\x6d\xd0\xef\x35\xd4\x3d\xc9\x00\x00\x00"
      "\x00\x00\x00\x00\x00\x00\x0d\x14\x11\x4b\xbe\x11\x95\x17\xa4\xac\xb7\xcc"
      "\x85\x66\x91\x4b\xc1\x16\x4f\xb4\x7f\x03\x00\x00\xff\xff\xf3\x49\x46"
      "\xf8",
      1188);
  syz_mount_image(0x20000000, 0x20000080, 0x1000000, 0x20000200, 1, 0x4a4,
                  0x20000a40);
  memcpy((void*)0x20000280,
         "\023\023w\305\3745\324\024T\325\324\035)\255\032`)"
         "Y\201F\346\276\026nA\255\r\275@T\003<\2373\273\332\202$"
         "\242\363\327r\347cnH\263<\277p\203r\350\361\271\223>"
         "\305\022wC\276\"\006 \236\360-\371\313\362\366\350\200\3238/\000",
         78);
  syscall(__NR_mkdir, 0x20000280ul, 0ul);
  memcpy((void*)0x20000040, "./file0\000", 8);
  memcpy((void*)0x20000300,
         "\023\023w\305\3745\324\024T\325\324\035)\255\032`)"
         "Y\201F\346\276\026nA\255\r\275@T\003<\2373\273\332\202$"
         "\242\363\327r\347cnH\263<\277p\203r\350\361\271\223>"
         "\305\022wC\276\"\006 \236\360-\371\313\362\366\350\200\3238/\000",
         78);
  inject_fault(11);
  syscall(__NR_rename, 0x20000040ul, 0x20000300ul);
  close_fds();
}
int main(void)
{
  syscall(__NR_mmap, 0x1ffff000ul, 0x1000ul, 0ul, 0x32ul, -1, 0ul);
  syscall(__NR_mmap, 0x20000000ul, 0x1000000ul, 7ul, 0x32ul, -1, 0ul);
  syscall(__NR_mmap, 0x21000000ul, 0x1000ul, 0ul, 0x32ul, -1, 0ul);
  setup_fault();
  do_sandbox_none();
  return 0;
}